I can’t verify these claims, but according to various tumblr blogs, this photo shows a strongbox made in Nuremberg in around 1540. It’s made of sheets of forged iron riveted together. In addition to the three top locks, there are two concealed ones that must be turned to open the box. One is located in a hidden keyhole in the front and one disguised rivet must be rotated.

It’s similar to this strongbox pictured above, about which I can be more certain. The Metropolitan Museum of Art in New York City owns this strongbox, also from Nuremberg, which dates back late Sixteenth or early Seventeenth Centuries. The locking mechanism on the top of the lid is not only complex, but beautifully decorated.